Martínez grew up in Dorado, Puerto Rico. He was not a highly regarded prospect, and signed with the Mariners as a free agent in 1982 for a small signing bonus. He made his major league debut in 1987, but did not establish himself as a full-time player until 1990. In the 1995 American League Division Series, he hit "The Double", which won the series and increased public support for Mariners baseball as they attempted to find a new stadium. He continued to play until 2004, when injuries forced him to retire.

Martínez was born in New York City on January 2, 1963, to José and Christina Salgado Martinez, who were from Puerto Rico. His parents divorced when he was two years old, and he was taken in by his grandparents, who lived in the barrio of Maguayo in Dorado, Puerto Rico.[2] Martínez taught himself how to speak English and how to use computers.[3] When was 11 years old, his parents reconciled. His brother and sister returned to New York to live with their parents, but Edgar opted to remain in Dorado with his grandparents.[4]

At the suggestion of the owner of his semiprofessional team, Martínez attended a tryout held by the Seattle Mariners of Major League Baseball (MLB). The Mariners signed him to a contract with a $4,000 signing bonus on December 12, 1982.[5][6] He initially considered declining the offer, due to the money he was making in Puerto Rico, but Carmelo convinced him to sign.[5]

Playing for Calgary in 1987, Martínez had a .327 batting average, 10 home runs, and 31 doubles in 129 games.[2] He led Calgary in batting average, as well as hits, doubles, batting average, on base percentage, games played, and walks.[8]

Martínez made his major league debut on September 12, 1987, and proceeded to hit .372 over his first 13 career games.[2] However, the Mariners were committed to using Jim Presley as their third baseman.[9] In 1988, Martínez began the season with Calgary, but was called up to the major leagues in early May. He played in four games with the Mariners before being returned to Calgary,[10] where he hit .363, the best batting average in the PCL.[2] In September he was called up again, and over 10 games hit .389. In his second MLB season, he hit .281 with a .351 on-base percentage (OBP) and a .406 slugging percentage over 14 games.[10]

The Mariners named Martínez their starting third baseman on their Opening Day roster in 1989.[6] He struggled and was sent back down to Calgary in May.[6] He hit .345 over 32 games for the Cannons and .240 in 65 games for the Mariners in 1989. After the regular season, Martínez played winter baseball in the Puerto Rican Baseball League. He batted .424 in 43 games, leading the league, and was named co-most valuable player with Carlos Baerga.[2]

In 1990, Martínez signed a one-year contract for $90,000.[2] Though Presley was no longer a Mariner, Darnell Coles began the season as the Mariners' starting third baseman, with managerJim Lefebvre telling The Seattle Times during spring training: "I think Darnell Coles is going to surprise a lot of people. He knows there is no one in the wings, just Edgar Martinez to back him up." However, Coles committed five errors in Seattle's first six games.[7] Lefebvre moved Coles to the outfield and began playing Martínez at third base.[2] Over 144 games, Martínez hit .302, and had a .397 on-base percentage, both of which led the team.[11]

Martínez signed a two-year contract worth $850,000 before the 1991 season. In 1991, he won his first MLB Player of the Week Award for the week ending July 14.[12] He finished the 1991 season hitting .307/.405/.452, all career highs. In 1992, Martínez was selected to his first All-Star Game,[13] and won his first MLB Player of the Month Award for July and his second for August,[14] During the season, Martínez signed a three-year contract with Seattle worth $10 million, the largest contract given out by Seattle to that point.[2]

During an exhibition game at BC Place Stadium in Vancouver, British Columbia, before the 1993 season, Martínez tore his hamstring on an unzipped seam in the turf between first and second base.[19] He missed 42 games at the start of the season, and was placed on the disabled list two more times before the season ended. In 1994, in his first plate appearance of the season, opposing pitcher Dennis Martínez hit him in the right wrist,[20] and he was placed on the disabled list. Between the injuries and the 1994 MLB strike, he played in 131 games during the 1993 and 1994 seasons.[21] In 89 games played in 1994, he played 65 games as a third baseman and 23 as a designated hitter, with one appearance as a pinch runner.[2]

In the 1995 American League Division Series (ALDS) against the New York Yankees, Martínez hit .571 and was on base 18 times in five games. In Game 4 of that series, he hit a three-run home run, then a grand slam home run that broke a 6–6 tie, en route to an 11–8 victory. His seven runs batted in (RBIs) in that game set a single-game postseason record. The win knotted the best-of-five series at two games apiece and forced Game 5. Down 5–4 in the 11th inning of that decisive game, Martínez hit a two-run double off Jack McDowell, winning the game for the Mariners, 6–5, and series, 3–2. The win sent the Mariners to the American League Championship Series for the first time in franchise history, against the Cleveland Indians, a series they would eventually lose in six games.

A lot of people remember that double when they talk about my career, I'd say, yeah, that would define my career.

In 1996, Martínez batted .327 and was selected for the 1996 MLB All-Star Game. He played one game at third base during the season, during which he collided with John Marzano, breaking four ribs and missing 21 games. On August 21, 1996, Martínez recorded his 1,000th career MLB hit. Martínez was selected to the 1997 MLB All-Star Game and won the Silver Slugger Award at the end of the 1997 season. He finished second in the AL with a .330 average. The Mariners made the 1997 ALDS, but lost to the Baltimore Orioles in four games. Martínez batted .188 in the series.[6] He won his second Outstanding Designated Hitter Award.[24] In 1998, Martínez batted .320 with 29 home runs.[6] He led the AL with a .429 OBP,[26] and won his third Outstanding Designated Hitter Award.[24]

In 1999, Martínez was diagnosed with strabismus,[27] a condition which causes the eyes to not properly align. For Martínez, his right eye would intermittently drift and cause him to lose depth perception.[5] For the 1999 season, he led the AL with a .447 OBP and batted .337. He recorded his 1,500th hit on August 14.[6] In 2000, Martínez earned his fifth All-Star Game selection. He hit 37 home runs, his single-season best, and led the American League with 145 RBIs.[2] The Mariners reached the postseason, and Martínez batted .364 in the 2000 ALDS, defeating the Chicago White Sox.[6] The Mariners lost to the Yankees in the 2000 American League Championship Series (ALCS). Martínez finished sixth in AL MVP Award balloting,[2] and won the Outstanding Designated Hitter Award.[24]

In 2001, Martínez was again elected to the All-Star Game.[2] He batted .306 with 113 RBIs,[7] his tenth season with a .300 or better batting average (his seventh consecutive) and his sixth season with 100 RBIs.[6] Seattle tied the major league record set by the 1906 Chicago Cubs with 116 wins on the season. Martínez hit .313 with two home runs in the 2001 ALDS as Seattle defeated Cleveland, but he batted .150 in the 2001 ALCS as they lost to the Yankees.[2][6] He won the Silver Slugger Award and the Outstanding Designated Hitter Award in 2001.[24][28]

Martínez dealt with leg injuries in 2002, playing in 97 games. He left a game after pulling his hamstring and had surgery to repair a ruptured tendon in his left knee. Though he was batting .301 on September 8, he entered a slump late in the season and ended the year with a .277 batting average. In 2003, Martínez again dealt with hamstring injuries. He batted .304 in the first half of the season and was named to the 2003 MLB All-Star Game. On May 2, Martínez had his 2,000th career hit. He broke a toe when it was hit by a foul ball in September, which limited him until the end of the season.[6] He ended the season with a .294 batting average, 24 home runs, and a .403 OBP.[2] He won his fifth Silver Slugger Award in 2003.[29]

In 2004, Martínez struggled with a sore back, leg injuries, and difficulties with his eyesight.[6] The Mariners struggled, falling out of the postseason chase, and the team began to give playing time at designated hitter to Bucky Jacobsen.[4] On August 9, 2004, Martínez announced his retirement, effective at the end of the season. Martínez said this about his choice of retiring and career in Seattle:

It is hard, very hard, I feel in my mind and my heart I want to keep playing. But my body is saying something differently, so I feel this is a good decision.

On June 20, 2015, the Mariners hired Martínez as their hitting coach, reassigning Howard Johnson.[32] The team's offense improved from a .233 batting average and 3.4 runs scored per game in the 68 games coached by Johnson to a .260 average and 4.6 runs per game with Martínez in 94 games. Though Jerry Dipoto, newly hired as general manager, fired Lloyd McClendon as manager after the season, he retained Martínez.[33] Martínez coached the Mariners through to the end of the 2018 season. Out of a desire to spend more time with his family, Martínez moved from hitting coach to a hitting advisor role with the Mariners organization after the 2018 season.[34]

Mariano Rivera, when asked whether there was anyone he was afraid to face, said that he was never afraid, but "I will put it like this: The only guy that I didn't want to face, when a tough situation comes, was Edgar Martínez. The reason is because I couldn't get him out. (laughs) I couldn't get him out. It didn't matter how I threw the ball. I couldn't get him out. Oh, my god, he had more than my number. He had my breakfast, lunch and dinner. He got everything from me."[35] Versus Rivera, Martínez was able to log a .579 batting average, with 11 hits during 19 at bats.[36] Hall of Fame pitcher Pedro Martínez (no relation) also named Edgar Martínez as one of the toughest hitters he had to pitch against in his career because, Pedro said, he was very disciplined at the plate and "would foul off pitches that would wipe out anybody else."[37]

Martínez was inducted into the Hispanic Heritage Baseball Museum Hall of Fame on September 9, 2003, in a pregame on field ceremony at Safeco Field.[38] In October 2004, following his retirement, a section of South Atlantic Street (State Route 519) in Seattle adjacent to Safeco Field was renamed Edgar Martínez Drive South.[39] At his retirement ceremony, a portrait "featuring his high stepping batting style" painted by artist Michele Rushworth was presented to him by the Mariners.[40] In 2004, MLB renamed the Outstanding Designated Hitter Award in Martínez's honor.[41] In 2005, fans voted Martínez as the third baseman on the Latino Legends Team.[42]

The Mariners did not issue Martínez' uniform number, 11, to anyone since he retired. Under Mariners' team policy, he was not eligible to have his uniform number formally retired until 2010, when he became eligible for the National Baseball Hall of Fame for the first time.[43] The Mariners inducted Martínez into the Seattle Mariners Hall of Fame on June 2, 2007,[44] and retired Martinez's #11 jersey on August 12, 2017.[43]

First eligible to be elected into the Hall of Fame in the 2010 Baseball Hall of Fame balloting, and with 75% of the vote required for induction, Martínez received 36.2% of the vote. While some sports writers felt that his batting numbers do not overcome the one-dimensional aspect of his career as a DH, others have compared this to the specialty of closers whose contribution to their teams victories resides on working one inning to preserve an advantage and the fact that these late inning relievers are not involved in other facets of the game such as hitting and base running.[45] By the 2018 Baseball Hall of Fame balloting, his ninth year on the ballot, Martínez's vote total increased to 70.4%. The 2019 ballot, his last chance for election by the Baseball Writers' Association of America, elected him to the Hall of Fame, appearing on 85.4% of the ballots cast.[46][47] He became the second player to enter the Hall of Fame as a Mariner, after Ken Griffey Jr.,[48] and the sixth player to be elected in his final year of eligibility, after Red Ruffing, Joe Medwick, Ralph Kiner, Jim Rice, and Tim Raines.[49]

Martínez met Holli (née) Beeler on a blind date; they married in October 1992.[2][50] They live in Kirkland, Washington, with their three children: Alex, Tessa, and Jacqueline. He runs Branded Solutions by Edgar Martínez, a byproduct of his family's embroidery business, in nearby Tacoma.[51] Martínez is one of the founders of Plaza Bank, founded in 2005 as Washington's first Hispanic bank.[52]

In 2006, Martínez cofounded Branded Solutions, a corporate merchandise category, with two executives from ImageSource.[54] He sold the company to ImageSource in 2010.[55] For the 2013 season, the Mariners worked with Martínez, local chef Ethan Stowell and bartender Anu Apte to create "Edgar's Cantina" at Safeco Field.[56]